Switch-actuating mechanism



April 1930- G. H. WH'ITTINGHAM 1,753,180

SWITCH ACTUATI'NG MECHANISM I Filed Dec. 8, 1926 2 Sheets-Sheet l alikeMun;

April 1, 1930. G. H. WHITTINGHAM 1,753,180

SWITCH ACTUATING MECHANISM Filed Dec. 8, 1926 2 Sheets-Sheet 2 a ike awePatented Apr. 1, 1930 UNITED STATES PATENT OFFICE GEORGE WHITTINGHAM, OFBALTIMORE, MARYLAND, ASSIGNOR TO MONITOR CON- TROLLER COMPANY, OFBALTIMORE, MARYLAND, A CORPORATION OF MARYLAND SWITCH-ACTUATIN GMECHANISM Application filed December a, 1926. Serial No. 153,304.

This invention relates to switch operating mechanism adaptedparticularly for use on alternating current circuits in connection withswitches having contactors of large size and 5 capacity which arenormally biased toward open position by gravity, or springs, and whichrequire large magnets and a considerable amount of electrical energy tomove them to their closed positions. In mechanism of this character, ifthe alternating current is left flowing through the coils of the magnetwhich moves the contactors to closed position, for the purpose ofkeeping them closed, the coil heats and is apt to burn out, and alsothere is involved an unnecessary waste of electrical energy. In order toavoid this and other objections to the use of a switch actuating magnetas a holding magnet, I provide a relatively long operating arm or lever,for actuating the switch contactors, and a small holding magnet having apivoted armature which is connected by a slot and pin connection to thefree end of said arm in such a way as to exert strong leverage on saidarm to keep it in closed position after it has been moved to suchposition by the main magnet.

, When the parts reach their closed positions, the circuit through themain magnet is interrupted automatically as hereinafter described.

The circuit of the main magnet may be interrupted automatically invarious ways, some of which are illustrated in the drawing. Inthe-preferred form of the invention, the

.coil of the holding magnet is in series with the coil of a relaymagnet, the function of the relay being to close the circuit of the mainmagnet when current is applied to the device, and to open this circuitafter the operating 40 arm has moved to closed position. In moving toclosed position, the operating arm swings the armature of the holdingmagnet toward the latter, thus reducing the reluctance of the magneticcircuit of the holding coil, with the result that when the armatureengages the pole piece of the holding magnet, the current flowlngthrough said coil and through the coil of the relay magnet is so reducedin volume that the latter magnet will magnet and increasing thereactance of its no longer hold the relay switch closed, and the saidswitch opens the circuit of the main magnet. The current flowing throughthe coils of the relay and holding magnets is, however, sufficient tocause the holding magnet to retain its armature and the operating arm inclosed positions until said circuit is entirely interrupted, by handswitch or otherwlse.

The invention, in so far as the interlock ing arrangement of theoperating arm and.

the armature of the holding magnet is concerned, is applicable tomechanisms in which the relay switch is omitted and the circuit throughthe main magnet is opened by other means, and it is also applicable toswitches and circuit breakers which are closed by hand. 4

In the accompanying drawing,

Fig. 1 is a side view of a switch operating mechanism adapted for remotecontrol, and embodying electro-magnetic means for closing andinterrupting the main switch magnet, the operating arm being shown inswitchclosing position, and, the circuits being shown diagrammaticallyFig. 2 is a similar view of the apparatus shown'in Fig. 1, the operatingarm being shown in open position;

Fig. 3 is aside view of a remote control apparatus like that shown inFigs. 1 and 2,

but with the addition of mechanical means for opening the circuit of themain magnet;

Fig. 4.- is a similar view of a modification in which the circuit of themain switch magnet is opened and closed by a switch actuated by theoperating arm;

Fig. 5 is a detail View showing the mechanism of Fig. 1 in frontelevation; and,

Fig. 6 is a side elevation of a mechanism in which a switch-operatingarm is manually closable, and the armature of a holdng magnet isconnected to said arm as in the previous figures.

Referring to Figs. 1, 2 and 5 of the drawing, a represents a switchactuating arm which is secured to a rock shaft 1, upon which any desirednumber of switch arm'sior contactors may be mounted, two of thesecontactors being indicated at 2. The arm a comprises two parallel metalstrips 3, between which is secured an armature 4, which is arranged nearthe pivotal end of the arm and opposite a pole piece of the mainelectromagnet b. The arm a is relatively long and extends to aconsiderable distance beyond the magnet b, and it has near its free enda roller 5, mounted upon a pin 6, which is fastened to the sides of thearm and extends through a guide loop 7, which latter is secured to thearmature 8 of a holding magnet 0. The arm a and the armature 8 are eachpivoted to swing toward the pivotal axis of the other, and the polepiece10 of the holding magnet is between the pivotal points of the arm andarmature. The guide loop 7 on the armature of the holding magnetconnects said armature with the arm a so that when the latter is rockedfrom the position shown in Fig 1, to the position shown in Fig. 2, orvice versa, the armature 8 will also be rocked about its pivotal point.The normal position of the arm a is that shown in Fig. 2, where it isheld by its own weight and by the weight of the contactors mounted uponthe shaft 1. When the magnet 12 is energized, this magnet, acting uponthe armature 4, causes the aim a to swing from the position shown inFig. 2 to the position shown in Fig. 1, and in this movement the roller5 moves along the guide loop 7 toward the pivoted end of the armature 8,and the latter moves down into contact with the pole piece 10, asillustrated in Fig. 1. In this position, it is to be noted that theroller on the free end of the arm a is near the pivotal point or fulcrum9 of the armature 8, while the free end of the latter is over the polepiece 10, at some distance from said pivotal point. When the magnet 0 isenergized, the armature 8 serves as a lever to hold the arm a firmly inthe position shown in Fig. 1, and a very small amount of current in thecoil of the holding magnet will suffice to hold the arm a in this switchclosing position, even when the contactors mounted on the shaft 1 exerta strong pressure tending to rock the arm a about its axis and away fromthe holding magnet.

The circuit for the main magnet b extends from the supply wire 11through conductor 12 to the coil 13 of said magnet, thence by conductor14 to the stationary contact 15 of an electro-magnetic switch s, thencethrough contactor 16 of said switch, armature 17 and the core 18 of amagnet d, and thence to supply wire 19 which is grounded at 20 on saidcore. From the supply wire 11, a conductor 21 leads through a manuallycontrolled switch 22 to the coil 23 of magnet 0 and from said coil aconductor 24 leads to one terminal of coil 25 of magnet d, the otherterminal of which coil lies connected to supply wire 19, at the groundThe operation of the mechanism shown in Figs. 1, 2 and 5 is as follows:Normally, the

parts are in the position shown in Fig. 2. Upon closure of the handswitch 22, the coils of the magnets c and d, which are in series, areenergized. As the armature 8 is held at a considerable distance from thepole piece 10 of the holding magnet by the arm a, the position of thearmature is not affected by the attraction of the magnet. The armature17 of the relay magnet d, however, is attracted and closes the switch 8,thus completing the circuit through the coil of the main magnet b. Whenthis occurs, the main magnet attracts the armature on the arm a and'thelatter rocks the shaft 1, closing the switch contactors 2 thereon, andit also moves the armature 8 into contact with the pole piece 10 of theholding magnet 0. As the armature 8 swings toward the pole piece 10, thereluctance of the magnetic circuit of the holding magnet is decreasedand the reactance of the coil 23 i increased, cutting down the currentwhich flows through said coil and the coil 25 of the relay magnet. Whenthe armature 8 is practically in contact with the pole piece 10, thereactance of the coil 23 is so great that only a small quantity ofcurrent can flow through the circuit in which it is included,

- which circuit also includes the coil of the relay magnet. Thisreduction in the current volume flowing through the latter coil weakensthe magnet d and its armature 17 immediately falls away from the magnetand opens the switch 8, thus breaking the circuit through the mainmagnet b. The holding magnet alone then holds the arm a in the switchclosin position, with very little current flowing in the coil of saidmagnet, owing to the leverage exerted by the armature 8 upon the freeend of the arm a. To release the arm a and to permit it to move tonormal position, the operator opens the hand switch 22, which breaks thecircuit through the coil of the holding magnet and the arm a rocks withthe shaftv 1 to the switch opening position and at the same time swingsthe armature 8 away from the pole piece 10 of the holding magnet.

The main magnet b is necessarily of large size and its coils require arelatively large amount of current in order that the magnet may havesufiicient strength to rock the arm a and shaft 1, with the contactorsthereon, to theclosed positions of the latter.- It will be seen that inthe present switch mechanism, this magnet is only energized momentarily,to close the contactors, and thereafter the contactors are held closedby the small holding magnet through the coils of which the small amountof current flows. It is also to be noted that the coil of the holdingmagnet and the coil of the relay ma net are in series and that if thecoil of either magnet burns out, causing an interruption of the circiut,the holding magnet will release the armature or keeper 8 and theoperating arm a will swing to the open position. Thereafter, it will notbe possible to operate the mechanism by closing the switch 22 until theburnt-out coil is replaced because the relay will not operate to closethe circuit of the coil of the main magnet.

In Fig. 3 of the drawing, the mechanism and circuits are the same as inFigs. 1 and 2, with the addition of a sliding rod 26, arranged betweenthe operating arm a and the relay armature 17 for positively moving thelatter to open position when the operating arm moves to closed position.Thus, the relay armature 17 has an extension 17 a in line with the rod26, and when the latter moves to closed position it engages the rod andcauses it to strike the extension 17 of the relay armature and move thelatter to open position, thus interrupting the circuit of the mainmagnet at the switch a. This mechanical operation of the relay armaturemay be desirable in some cases, to insure the opening of the switch incase the contacts stick together. 'In this figure of the drawing, thearm a connected to the armature 8 of the holding magnet by the loop 7and guide roller 5, as in Figs. 1 and 2, and when the arm a is attractedby the main magnet b, the circuit of the main magnet will be interruptedat the switch 8, and the holding magnet will hold the operating arm inclosed position, with little current flowing through the coil of theholding magnet and the coil of the relay, as described in connectionwith Figs. 1 and 2.

In Fig. 4, the operating arm a is connected to the armature or keeper 8of the holding magnet by the guide loop 7 and roller 5. In this figure,the relay magnet is omitted and the circiut for the main magnet b iscompleted by a hand switch 28 through a normally closed switch 8 Thislatter switch comprises contacts 29 and 30 which are normally bridged bya contactblade 31, secured to the armature 8 of the holding magnet. Whenthe hand switch 28 is closed, it connects the supply wire 37 toconductor 32 and current flows through conductor 32 to the contact 29 ofswitch 8 thence through blade 31, contact 30 and conductor 33 to thecoil 34 of the main magnet, and thence by conductor 35 to supply wire36. The coil 23 of the holding magnet is connected by wire 38 to supplywire 36 and by wire 39 to conductor 32. The closure of the switch 28therefore connects the holding coil to the supply wires. When the mainmagnet is energized, it attracts the operating arm a, which latter movesthe armature 8 against the pole 10 of the holding magnet and at the sametime the switch blade 31, attached to said armature, opens the circuitof the main magnet at the switch 8 The main magnet thus becomesdeenergized and the holding magnet retains the arm a in its closedposition. Owing to the leverage exerted by the armature 8 upon the freeend of the arm a, a very small quantity of current flowing through theholding coil will cause the arm a to be held securely in closedposition.

In Fig. 6 is shown a switch arm a, which is movable to closed positionby a handle 40, this arm carrying acontact blade 41, fo'r engaging abrush contact 42 and a carbon contact 43. This switch arm isnormallyheld in open position by a spring 44. The free end of the arm isconnected to the armature 8 of a holding magnet 0 in the same mannerthat the arm a and the armature 8 are connected in the previouslydescribed figures, and the pole 10 of the holding magnet is arrangedintermediate the pivotal points 45 and 46 of the arm a and armature 8,respectively. The supply wire 51 leads to switch arm a, and when saidarm is in closed position, the current flows through the switch tooverload coil 48 and wire 52 to a motor or other load. A conductor 50leads from conductor 52 through the coil of the holding magnet tooverload switch 48 and thence to lead wire 49.

Vhen the switch arm a is moved manually to closed position, the circuitthrough the coil of the holding magnet is completed and the armature 8is swung into contact with the pole piece 10, which holds the armature,and the arm a is thereby held in the switch closing position, anegligible amount of current being required in the coil of the holdingmagnet for this purpose. \Vhen the circuit of the holding magnet isinterrupted, as by the opening of the overload switch 48, said magnetwill release the armature 8 and the spring 44 will then rock the arm aand the armature 8 to the position shown in Fig. 2.

What I claim is:

1. An alternating current switch operating mechanism comprising a mainmagnet, a holding magnet, an operating lever movable to closed positionby said main magnet and adapted to be held in closed position by saidholding magnet, a normally open switch for closing the circuit of saidmain magnet, a

magnet for closing said switch, the coils of said latter magnet and ofsaid holding magnet being in series with one another, and means forenergizing and de-energizing said coils.

2. An alternating current switch-operating mechanism comprising a mainmagnet, a holding magnet, armatures for said magnets, means linking saidarmatures so that they move together to and from their respectivemagnets, a normally open switch for closing the circuit of said mainmagnet, a magnet for closing said switch, a circuit including the coilsof said holding and switch-closing magnets, and a switch for opening andclosing the latter circuit.

3. An alternating current switch operating mechanism comprising a mainmagnet, a holding magnet, an operating'lever movable to closed positionby the main magnet, a

holding armature movable to closed position by said operating lever andadapted to hold the latter in closed position while the holding magnetis energized, a normally open switch for closing the circuit of the mainmagnet, a magnet for closing said switch, a circuit including the coilsof the latter magnet and of the holding magnet, and means for openingand closing said latter circuit.

m 4:. An alternating current switch-operating mechanism comprising arelatively long operating lever, a main magnet for moving the same toswitch-closing position, a holding magnet having an armature pivotedadjacent the free end of the lever and having a sliding connection Witha part on the free end of said lever, a circuit for said main magnetincluding a normally open switch, a magnet for closing the latterswitch, a circuit including the coils of the last mentioned magnet andof the holding magnet, and means for opening and closing the lastmentioned circuit.

5. A switch-operating mechanism comprising a main magnet, a holdingmagnet, an op- 5 erating lever movable to switch-closing position bysaid main magnet, an armature for the holding magnet pivoted adjacentthe holding magnet and linked with said lever so that said lever andarmature move together,

and means for de-energizing said main magnet when said lever is moved toswitch-closing position.

In testimony whereof I hereunto afiix my signature.

as GEORGE H. WHITTINGHAM.

